lewis



3. Sheets-Sheet 1.

(No Model.)

F. M. LEWIS.

ELECTRIC ARG. LAMP.

Patented Apr. 23, 1895.

(No Model.) l 3 Sheets-Sheet 2.

F. M. LEWIS.

ELECTRIC ARG LAMP.

No.538,023. Patented Apr. 23, 1895.

(No Model.) a sheets-sheet 3.

F. M. LEWIS.

ELECTRIC ARG LAMP.

Patented-Apr. 23, 1895.

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UNITED STATES PATENT OFFICE.

FRANK MICHAEL LEWIS, OF LONDON, ENGLAND.

.ELECTRIC-ARC LAM P.

SPECIFICATION forming part of Letters Patent No. 538,023, dated April 23, 1895. Application tiled October 12, 1894. Serial No.525.677 (No model.) Patented in England December 4, 1893, No. 23,239.

T0 all whom it may concern:

Be it known that I, FRANK MICHAEL LEWIs, a subject of the Queen of Great Britain and Ireland, residing at Leinster Gardens, Hy de Park, London, England, have invented a new and useful Improvement in Electric-Arc Lamps, (for which I have obtained a patent in Great Britain, No. 23,239, bearing date December 4, 1893,) of which the following is a specification.

My invention refers to means for controlling the movement of one or both carbons in arc lamps, and has for its object to insure greater regularity in the feed as the carbons are consumed, to eifect this with very small variation of the electromotive force across the terminals of the lamp, and to insure greater certainty of the striking of the arc (i. e. the movement of the carbons to the proper distance apart directly after contact).

lvlyinventionlconsists essentially in the introduction as part of the controlling mechanism of a rocking arm connected to the plunger of the solenoid and a differential or epicyclic train of wheels in such a manner that the feed of the carbons toward each other is effected through one side of the train, While the striking or moving apart of the carbons is eect-ed from the opposite side of the train, the said rocking arm controlling the former (i. c. the feed) and operating the latter (1l. c. the strik- Ing In order that myinvention and its applicability to various kinds of arc lamps may be more readily and clearly understood I have annexed hereto the accompanying sheets of drawings, in Which- Figure 1 is a side elevation, Fig. 2 an end elevation, and Fig. 3 a plan, illustrating my invention as applied to a focusing arc lamp (i. e. in which both carbons are moved) and in which the solenoid Winding is traversed by a shunt current across the lamp circuit. Fig. 4 isaside elevation, Fig. 5 an end elevation,and Fig. 6 is a plan, illustrating my invention as applied to a non-focusing arc lamp (t. c. in which only the top carbon is moved) having a wire or cord suspension for the top carbon and in which the solenoid winding is in the maincircuit.

In all the views the same reference letter is used for the same or corresponding parts, so that both illustrations may as far as possible be described concurrently.

A is the lamp base from which the guide rods B are suspended and on which are mounted the side frames O for carrying the mechanism.

a is the before mentioned rocking beam,` mounted loose on the end or ends of the main axle l), the latter being carried in bearings in the standards O. One end of the beam a is attached to the plunger c of the solenoid D. On the axle b is mounted the differential or epicyclic train of wheels. This consists of a central Wheel d round which the Wire or tape e passes to the top carbon holder E, Figs. a and 5; or to guide frames F carrying both carbon holders, of which only the top frame is shown in Fig. l. The center wheel or drum CZ carries a small bevel (or crown) Wheel i, which gears with two larger bevel (or crown) wheels g and h, mounted loose on the axle b. The wheei gis cast with or attached to the ratchet wheel j, and the wheel h with or to the large toothed Wheel It, all being loose on the axle l). This toothed Wheel 7o gears With the pinion fm, on the escapement wheel axle n, Figs. l and 2; or it may be geared to a fan axle also lettered n, Figs. 4 and 5, by means ofintermediate axle and Wheels.

The rocking beam a is provided with a pawl o, which engages with and moves the ratchet Wheelj (so as to separate the carbons), when the plunger c of the solenoid in Figs. l to 3 moves downward; and in Figs. 4 to 6 moves upward. A second paWl p prevents the return of the ratchet Wheel j, when the rocking beam a and pawl o move in the opposite direction.

In Figs. l to 3 a brake Wheel q is attached to the wheels h and 7c, the movement of which is controlled by the brake block r, which is mounted on the cross shaft t. A double armed lever s is fixed on the cross shaft t near the opposite end, one arm of which is bent upward so as to come beneath and close against the under side of the rocking beam a; while the end of the opposite arm is attached toa spiral spring u, which latter is fixed by its lower end to the base A. This spring u, constantly tends to keep the brake block r pressed against the brake wheel q, and the bent arm of the lever IOO s against the underside of the rockingbeaml a; while the upward movement of the solenoid plunger c causes the rocking beam a to depress the said bent arm and to take the brake block fr' oif the brake wheel q.

In Figs. 4 to 6 which show the lamp mechanism provided with a fan instead of an escapement, the checking of the feed is effected by means of the catch y, which is attached to the rocking beam a. Vh-en the plunger e is about in its lowest position, lthe catch y is clear off the fan c and allows this to rotate and the feed to take place. When the plunger` c rises a slight distance, the catch y stops the rotation of thev fan .fr and the feed of the carbon.

e' is a dash pot, the piston of which is attached to the rocking beam a by means of a slotted link, and a pin passing through the slot and attached to the rocking beam a.

In Figs. et to G the center wheel d is keyed or lixed tothe axle b, and a coiled spring K is fixed tothe end of the axle b and to a stud in one of the standards C. This coiled spring serves to draw up the tape e, when the carbon holder E is pushed up for recarboning.

rlhe operation of my lamp is as follows:

Referring first to Figs. I to 3, in which the solenoid windingis traversed by a shunt current, when no current is passing, so that the core or plunger e occupies its lowest position, the spring u presses the brake block r against the brake wheel q, and locks the feed side of the differential or epicyelic train. As soon as the current is switched on, the plunger c rises, and lifts its end of the rocking beam a, and depresses the opposite end; which pushes down the bent arm of the lever s, so as to take oif the brake fr, and allows the lamp to feed; the ratchet wheel t' being kept stationary by the catch o. The solenoid winding being in shunt, the current traversing it weakens as the carbons approach, until it allows the core Z1 to fall, and moves the rocking beam a so as to allow the brake r to stop the feed side of,

the train; while the pawl 0 rotates the ratchet wheel j so as to move the carbons apart. lVhen the arc becomes too long, the increased strength of the current traversing the solenoid winding again raises the plunger c, and as just explained allows the lampto feed.

Referring to Figs. et to 6 in which the solenoid Winding is in the main current, when no current is passing through the winding, the core c of the solenoid occupies its lowest position see Fig. 4, the catch y being clear off the fan 00, so that the feed gear is released and the weight of the top carbon holder feeds down the top carbon until it meets the lower carbon, or until the strength of the current begins to raise the solenoid plunger. During this time the catchp prevents the rotation of the ratchet wheelj. Directly after the plunger c begins to rise, it raises the arm or beam e at the corresponding end, so that the catch y stops the fan @c and the feed side of the differential train, and at the same time the catch 0 rotates the ratchet wheelj, thus raising the top carbon holder, separating the carbons. Then the are grows too long, the plunger c falls, the catch p preventing a reverse movement of the ratchet wheelj, and on the plunger descending sufficiently far, the catch y again moves clearoff the fan o: and allows the lamp to feed, until the current again raises the plunger c.

It will be evident that the pulley or drum d may be replaced by a toothed pinion gearing into a rac-k or racks attached to the top of both carbon holders; further that the arrangement ofthe epicyclic gear shown is not the only arrangement possible, but other forms may be used. For example, the bevel wheels g, h, may be replaced by ordinary spur wheels, and the bevel pinion t' by a horizontai shaft having an ordinary straight pinion wheel keyed at each end and engaging respectively with said spur wheels g and 7L.

The object of the epicyclic gear is to make the striking of the lamp independent of the feed, and this can be effected by an epicyelic gear so arranged that the striking is donc from one side of the train and the feeding from the other side. The operation of the epicyclic wheel is the same as in any epicyclic gear, for example that which sometimes forms part of a tricycle. Then both side wheels move at the same speed, the intermediate wheel does not move about its own axis. When one of the side wheels moves faster than the other the 'intermediate wheel turns in one direction or the other proportionally to their difference of rotation.

The chief practical advantage of the epicyelic gear in my lamp is that, the striking and feeding devices being independent though connected, the striking mechanism may at any time be pulled up farther in case of overfee'ding. Another advantage is that when the feed has to be checked or stopped there is only the friction of the pivots of the walking beam a to be overcome, and not, as in many other lamps, the friction of the whole lamp mechanism. Moreover, with small fluctuations or irregularities in the'current the pawl 0 merely rides up and down over the curved surfaceof a tooth and therefore does not keep moving the carbons apart., thus causing the light to be unsteady.

I am aware that prior to my invention differential or epicyclic gear has been proposed for arc lamps in combination with two solenoids and two plnngers, or with two electric controlling devices. I do not therefore claim the general use of differential or epicyclic gear in connection with arc lamps; but

What I do claim as my invention, and desire to secure by Letters Patent, is-

1. In arc lamps the combination of a rocking beam connected at one end with the plunger of a solenoid, a differential or epicyclic gear, the carbon holders and their suspension devices connectedwith the said center wheel, a ratchet wheel on one side of said gear acted upon by a ratchet pawl connected to said IOO los

IIO

rocking beam, a toothed. wheel on the opposite side of said gear, connected directly or indirectly With an escapement, fan or other feed checking or steadying device, andastop or brake device acting on the feed gear, such device or feed gear being controlled by the movement of the said rocking beam orof the solenoid plunger.

2. In arc lamps the combination of a rocking beam co carrying a pawl 0 and connected at one end with the plunger@ of a solenoid D, a differential or epicyclic train of wheels (Lt, g, h, of which CZ may be a rack pinion or a pulley, a fixed pawl p, a ratchet Wheel j at one side of said train of Wheels, a toothed wheel at the opposite side of said train of Wheels and connected with a fan or escapement axle n, and means for releasing and stopping the feed gear consisting of a brake wheel q, block r and lever s, actuated by the aforesaid beam a and spring u, or of a catch fy attached to the rocking beam a, all substantially as set forth.

3. In arc lamps the combination of a rocking beam a carrying a paWl o and connected at one end with the plunger@ of a solenoid D, a differential or epicyclic train of Wheels dft', g, h, of which d may be a rack pinion or a pulley, a fixed pawl p and a ratchet Wheel j and toothed Wheel 7a.

4. In arc lamps the combination of a single solenoid D and plunger c, a rocking beam a and a differential or epicyclic train such as d, i, g, 7L, for the purpose of enabling the striking and the feeding movements to take place independently of each other.

5. In arc lamps the combination of a single solenoid D and plunger c With a differential or epicyclic train of Wheels such as d, t', g, h, so that the movement of the plunger in one direction effects the striking of the arc through one side of the train, While the movement of the plunger in the opposite direction releases the feed gear through the opposite side of the train.

FRANK MICHAEL LEWTIS.

Witnesses:

WALTER B. IIANBURY, JOHN CLARK JEFFERSON. 

